1. Technical Field
The present invention relates to a display device, and particularly, to a contact touch sensitive display device and a method for determining contact.
2. Related Art
Recently, products in which a sensing device is integrated into a display device have been developed. Such a sensing device detects a pressure or a change of light generated by a touch, such as by a user's finger or a touch pen, such that electrical signals according to the touch are provided to the display device. The display device can detect whether or not a touch occurs or touch location information on the basis of the electric signals and transmit the information for the touch to an external device. The external device can transmit the image signal based on the contact information to the display device.
When detecting the touch existence and the position thereof by sensing the intensity of light, a change of brightness due to a shadow of the contact object is detected. However, although the contact object is not contacted, it may be determined that the contact existence is mistaken or the contact position is misjudged due to the shadow at another portion that is not the contact portion.
For example, if the end portion of the finger is taken on the edge of the display panel, a hard shadow is only generated on a narrow region. However, if the finger is only contacted under the state that the palm of the hand and the finger are all taken on the display panel, the hard shadow is generated on the portion covered by the palm of the hand as well as the finger. In this case, the possibility of the generation of an error is increased when determining the touch existence and the position thereof.
The above information disclosed in this Background section should only be for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.